Water discharging device

ABSTRACT

A water discharging device  2  that is installed so as to secure a predetermined opened space between a bowl  3  and the water discharging device  2 , and discharges water toward this bowl  3 , the water discharging device having a water discharge part  13  that jets waterdrops so as to spread the waterdrops at a predetermined angle θ from a water discharge port  13   a , and is set so as to discharge water at a predetermined flow rate, wherein an average flow speed X (m/sec) and an average particle size Y (μm) of the waterdrops jetted from the water discharge part  13  satisfy a conditional expression of “Y≦9300×X (−1.5) ”.

TECHNICAL FIELD

The present invention relates to a water discharging device, and moreparticularly to a water discharging device that discharges water so asto spread the water from a water discharge port.

BACKGROUND ART

Conventionally, various attempts are made for saving water in a waterdischarging device. Among these, spray water discharge in which mistywater is discharged at a low flow rate (water is discharged in such amanner that water spreads from a water discharge port) is effective forwater saving. This spray water discharge is useful in being capable ofdischarging water over a wide range while saving water.

For example, Patent Document 1 discloses a configuration of a nozzle forthe above spray water discharge. Additionally, for example, PatentDocument 2 discloses a hand wash basin that performs spray waterdischarge of electrolyzed water having a sterilizing function tosterilize hands.

CITATION LIST Patent Document

Patent Document 1: Japanese Patent Laid-Open No. 2004-050121

Patent Document 2: Japanese Patent Laid-Open No. 11-241381

SUMMARY OF INVENTION Technical Problem

The above spray water discharge is effective for water saving, but has ahigher flow speed than general water discharge (for example, foamy waterdischarge, shower water discharge, and the like), and therefore islikely to cause water splash. Therefore, the inventors of the presentinvention have considered to find out a parameter involved in watersplash in the spray water discharge and implement spray water dischargethat does not cause the water splash.

The present invention has been made in order to solve the above problem,and an object of the present invention is to suitably inhibit watersplash in a water discharging device that discharges water so as tospread the water from a water discharge port.

Solution to Problem

In order to achieve the above object, the present invention is a waterdischarging device that is provided so as to secure a predeterminedopened space with respect to a water receiving part, and dischargeswater toward the water receiving part, the water discharging deviceincludes a water discharge part that jets waterdrops so as to spread thewaterdrops at a predetermined angle from a water discharge port, and isset so as to discharge water at a predetermined flow rate, wherein anaverage flow speed X (m/sec) and an average particle size Y (μm) of thewaterdrops jetted from the water discharge part satisfy a followingconditional expression (1).

Y≦9300×X ^((−1.5))  (1)

In the present invention thus configured, in the water dischargingdevice that jets the waterdrops toward the water receiving part so as tospread the waterdrops at the predetermined angle from the waterdischarge port, the average flow speed and the average particle size ofthe waterdrops jetted from the water discharge part satisfy the aboveconditional expression (1), and therefore it is possible to suitablyinhibit water splash by the waterdrops jetted from the water dischargepart while securing water saving and water discharge over a wide range.

In the present invention, the average flow speed X and the averageparticle size Y of the waterdrops jetted from the water discharge partfurther satisfy a following conditional expression (2).

Y≧−360×X+1500  (2)

In the present invention thus configured, the average flow speed and theaverage particle size of the waterdrops jetted from the water dischargepart satisfy the above conditional expression (2), and therefore it ispossible to secure suitable washing performance (such as hand washingperformance) by water discharge of the water discharge part.

In the present invention, the average flow speed X of the waterdropsjetted from the water discharge part is equal to or larger than 1.7(m/sec).

In the present invention thus configured, the average flow speed of thewaterdrops jetted from the water discharge part is 1.7 (m/sec) or more,and therefore it is possible to suitably implement a water dischargeform in which the waterdrops are jetted so as to spread at thepredetermined angle from the water discharge port.

In the present invention, the average particle size Y of the waterdropsjetted from the water discharge part is equal to or larger than 35 (μm).

In the present invention thus configured, the average particle size ofthe waterdrops jetted from the water discharge part is 35 (μm) or more,and therefore the waterdrops jetted from the water discharge part can besuitably lowered without floating. Consequently, the waterdrops jettedfrom the water discharge part can suitably reach, for example, an objectsuch as hands of a user which stretch out toward the water dischargepart.

In the present invention, the average particle size Y of the waterdropsjetted from the water discharge part is equal to or smaller than 9000(μm).

In the present invention thus configured, the average particle size ofthe waterdrops jetted from the water discharge part is 9000 (μm) orless, and therefore it is possible to suitably inhibit split of thewaterdrops jetted from the water discharge part on the way.Consequently, it is possible to easily perform control for inhibitingwater splash.

In the present invention, the water discharge part jets the waterdropsso as to spread the waterdrops at from 40 to 50 degrees as thepredetermined angle.

In the present invention thus configured, an angle corresponding to arange when water is discharged from the water discharge port (dischargeangle) is set to 40 to 50 degrees, and therefore whole hands of a usercan be covered by water discharge from the water discharge part, andhand washing performance can be improved.

Advantageous Effects of Invention

According to the present invention, in a water discharging device thatjets waterdrops so as to spread the waterdrops from a water dischargeport, waterdrops having suitable flow speeds and particle sizes arejetted, so that it is possible to suitably inhibit water splash.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a hand wash basin to which a waterdischarging device according to the embodiment of the present inventionis applied, as viewed obliquely from above.

FIGS. 2A and 2B are diagrams for specifically illustrating aconfiguration of the water discharging device according to theembodiment of the present invention, in which FIG. 2A is a perspectiveview of this water discharging device as viewed obliquely from below,and FIG. 2B is a sectional view of this water discharging device takenalong the line IIB-IIB in FIG. 2A.

FIG. 3 is a longitudinal sectional view of a water discharge part forillustrating a principle of spray water discharge of the water dischargepart according to the embodiment of the present invention.

FIG. 4 is a whole configuration diagram of a measurement system used tomeasure water splash in the embodiment of the present invention.

FIGS. 5A and 5B each are a diagram illustrating an example of ameasurement result obtained by the measurement system according to theembodiment of the present invention.

FIGS. 6A and 6B each are a diagram illustrating another example of ameasurement result obtained by the measurement system according to theembodiment of the present invention.

FIG. 7 is an explanatory diagram of an upper limit boundary line of theaverage flow speed and the average particle size of waterdrops jettedfrom the water discharging device according to the embodiment of thepresent invention.

FIG. 8 is an explanatory diagram of a lower limit boundary line of theaverage flow speed and the average particle size of waterdrops jettedfrom the water discharging device according to the embodiment of thepresent invention.

FIG. 9 is a diagram illustrating a water discharge form by the waterdischarging device in a case where a flow rate applied to the waterdischarging device according to the embodiment of the present inventionis variously changed.

FIG. 10 is an explanatory diagram of a suitable range of the averageflow speed and the average particle size of the waterdrops jetted fromthe water discharging device according to the embodiment of the presentinvention.

FIG. 11 is a perspective view of a kitchen as viewed obliquely fromabove, the kitchen being a kitchen to which a water discharging deviceaccording to a modification in the embodiment of the present inventionis applied.

DESCRIPTION OF EMBODIMENTS

Hereinafter, a water discharging device according to the embodiment ofthe present invention will be described with reference to the attacheddrawings.

Device Configuration

First, a configuration of the water discharging device according to theembodiment of the present invention will be described with reference toFIG. 1 to FIG. 3.

FIG. 1 is a perspective view of a hand wash basin to which the waterdischarging device according to the embodiment of the present inventionis applied, as viewed obliquely from above. As illustrated in FIG. 1, ahand wash basin 1 mainly has a water discharging device 2 that mistilyperforms water discharge (spray water discharge/misty water discharge)so as to spread water from a water discharge port as illustrated byreference numeral M, and a bowl 3 that receives the water dischargedfrom this water discharging device 2, and drains the water from a drainport (not illustrated), and serves as a water receiving part.

FIGS. 2A and 2B are diagrams for specifically illustrating theconfiguration of the water discharging device according to theembodiment of the present invention. FIG. 2A is a perspective view ofthe water discharging device according to the embodiment of the presentinvention as viewed obliquely from below, and FIG. 2B is a sectionalview of this water discharging device taken along the line IIB-IIB inFIG. 2A.

As illustrated in FIGS. 2A and 2B, the water discharging device 2 has awater discharge pipe 11 that is a curved tubular member. In a front endof the water discharge pipe 11, a nozzle-like water discharge part 13configured to perform spray water discharge (misty water discharge) inwhich water spreads at a predetermined angle from a water discharge port13 a, and a sensor 14 that detects an object to be detected by utilizinginfrared light or the like are disposed. Additionally, inside the waterdischarge pipe 11, a flow path 15 that is connected to the waterdischarge part 13, and supplies water to the water discharge part 13 isdisposed. The water discharging device 2 detects the object to bedetected such as a human body by use of the sensor 14 to switch betweenexecution and stop of water discharge from the water discharge part 13.

Now, a principle of the spray water discharge of the water dischargepart 13 according to this embodiment will be described with reference toFIG. 3. FIG. 3 is a schematic diagram obtained by enlarging alongitudinal sectional view of the water discharge part 13 as viewedalong the water flow direction.

As illustrated in FIG. 3, in the water discharge part 13, a straightflow (refer to the arrow A11) is generated inside an internal flow path13 d by water that flows in from an inflow port 13 b provided in anupper end, and a rotational flow (refer to the arrow A12) is generatedinside the internal flow path 13 d by water that flows in from a slitpart 13 c formed on an outer peripheral surface of the upper end of theinternal flow path 13 d. The spray water discharge is performed in afull-cone manner from the water discharge port 13 a formed in a lowerend of the internal flow path 13 d, by a synergistic effect of such astraight flow and such a rotational flow. More specifically, whilespreading in a range larger than the cross-sectional area (openingdiameter) of the water discharge port 13 a, the water is intermittentlydischarged, in other words, waterdrops are jetted. In this case, asillustrated in FIG. 3, water spreads at a predetermined discharge angleθ from the water discharge port 13 a to be discharged. For example, thisdischarge angle θ may be set to 40 to 50 degrees to cover a whole ofhands of a user by the spray water discharge from the water dischargepart 13.

As described above, in this specification, word “spray water discharge”means that water is intermittently discharged so as to spread at thepredetermined angle θ from the water discharge port 13 a of the waterdischarge part 13, in other words, waterdrops are jetted.

The water discharge port 13 a of the water discharge part 13 has across-sectional area smaller than a water discharge port of a generalwater discharge part (for example, a water discharge part for performingfoamy water discharge or shower water discharge), and therefore hasstrong resistance, and generates pressure reducing action. Therefore, atleast one of a constant flow valve, a pressure regulating valve, and aconstant-pressure valve may be provided on an upstream side of the flowpath 15 of the above water discharging device 2 (not illustrated inFIGS. 2A and 2B), and water may be supplied to the water discharge part13 at a predetermined flow rate and/or with predetermined pressure.These valves are suitably adjusted, so that the flow speed and theparticle size (strictly, the average flow speed and the average particlesize) in the spray water discharge from the water discharge part 13 areset to respective desired values.

In the above example, an automatic water discharging device that detectsan object to be detected such as a human body by using the sensor 14 toautomatically switch between water discharge and stop of the waterdischarge is described as the water discharging device 2 (refer to FIGS.2A and 2B). However, the present invention is not limited to applicationto such an automatic water discharging device, and can be applied to awater discharging device that manually performs water discharge and stopof the water discharge.

Flow Speed and Particle Size of Spray Water Discharge

Now, the flow speed and the particle size of the spray water dischargeby the water discharge part 13 of the water discharging device 2according to the embodiment of the present invention will be described.More specifically, the average flow speed and the average particle sizeof waterdrops jetted from the water discharge part 13, which are to beapplied to the water discharging device 2 according to this embodiment,will be described. The inventors of the present invention investigateranges of the average flow speed and the average particle size ofwaterdrops that are to be jetted from the water discharge part 13 of thewater discharging device 2 by conducting various measurement describedbelow.

Herein, for the “average flow speed” of the waterdrops jetted from thewater discharge part 13 of the water discharging device 2, the averageflow speed at a position separated from the water discharge port 13 a ofthe water discharge part 13 by 100 (mm) is used. The “average flowspeed” of the waterdrops is equivalent to the moving speed of thewaterdrops. On the other hand, for the “average particle size” of thewaterdrops jetted from the water discharge part 13 of the waterdischarging device 2, a Sauter average value (total volume/total surfacearea) based on a particle size distribution, which is obtained by aFraunhofer analysis method utilizing a He—Ne laser is used. This“average particle size” of the waterdrop is equivalent to the diameterof the waterdrop.

The reason why such “average flow speed” and such “average particlesize” are used is because there is a distribution in each of the flowspeeds and the particle sizes of the waterdrops jetted from the waterdischarge part 13, and the flow speeds and the particle sizes are notuniform.

(1) Upper Limit Boundary Line of Flow Speed and Particle Size

First, an upper limit boundary line of the average flow speed and theaverage particle size of the waterdrops jetted from the water dischargepart 13 of the water discharging device 2 according to this embodimentwill be described. This upper limit boundary line is determined from aviewpoint of inhibiting water splash by the waterdrops jetted from thewater discharge part 13 of the water discharging device 2 according tothis embodiment.

FIG. 4 is a whole configuration diagram schematically illustrating ameasurement system used in order to measure water splash in theembodiment of the present invention.

As illustrated in FIG. 4, a measurement system 50 has a waterdischarging device 51 that jets a waterdrop WD, and can variously setthe flow speed and the particle size of this waterdrop WD, a frostedglass 52 with which the waterdrop WD jetted from this water dischargingdevice 51 collides, a scale 53 placed on this frosted glass 52, ahigh-speed camera 54 that photographs a range including at least asurface of the frosted glass 52 with which the waterdrop WD collides, alighting 55 that irradiates the frosted glass 52 from above with light,a lighting 56 that irradiates the frosted glass 52 from below withlight, and a PC (personal computer) 57 that receives supplied image dataphotographed by the high-speed camera 54 to process this image data.

More specifically, the frosted glass 52 has size of 300 (mm)×300 (mm)×5(mm). Additionally, a water discharge port of the water dischargingdevice 51 and a surface of the frosted glass 52 are separated by 100(mm). The high-speed camera 54 photographs with resolution of 1280(pixels)×800 (pixels) at a high speed of 10000 (frames/second).Furthermore, the pressure and the flow rate of water supplied to thewater discharging device 51 are adjusted, the opening diameter of awater discharge port applied to the water discharging device 51 ischanged, or the width of a slit applied to the inside of the waterdischarging device 51 is changed, so that the flow speed and theparticle size of the waterdrop WD jetted from the water dischargingdevice 51 are changed. The incident angle of the waterdrop WD jettedfrom the water discharging device 51 on the frosted glass 52 isconstant.

Herein, in this embodiment, a water film WF is formed on the frostedglass 52, and water splash when the waterdrop WD collides with thiswater film WF is measured. Not a hand in a dry state at an initial stageof hand washing (that is, a state where no water film is formed on asurface of the hand), but a hand in a wet state at a middle andsubsequent stage of the hand washing (that is, a state where the waterfilm is formed on the surface of the hand) is assumed, and the hand inthis wet state is simulated by the frosted glass 52 with the water filmWF formed thereon, so that water splash caused in the hand in the wetstate is attempted to be investigated.

Water splash is more likely to be caused in the dry state than the wetstate. This reason is as follows. In a case where a collision object isin the dry state, that is, in a state where a water film is not formedon a surface of the collision object, frictional force between water andthe collision object, adsorption power of water, and surface tension ofwater mainly act, so that water splash is unlikely to be caused. On theother hand, in a case where the collision object is in the wet state,that is, in a state where the water film is formed on the surface of thecollision object, the frictional force between water and the collisionobject (including the water film) is decreased, pressure generated atthe time of collision escapes toward an external air side (side on whichpressure is low), force generated at this time, which lifts the waterfilm becomes larger than the surface tension, so that the water filmbursts to be likely to cause water splash.

Now, the measurement procedure of water splash according to thisembodiment will be described. First, the water film WF is formed on thefrosted glass 52. In this case, the frosted glass 52 is hydrophilic, andtherefore water merely flows on the surface, so that the water film WFis formed. Then, the waterdrop WD is jetted from the water dischargingdevice 51 toward the frosted glass 52. In this case, in order to adjustfocus related to jetting of the waterdrop WD from the water dischargingdevice 51 to the frosted glass 52, a slit of 5 (mm)×10 (mm) is appliedto the water discharging device 51. From both the two lighting 55, 56,the frosted glass 52 is irradiated with light, so that the vicinity of acollision place of the waterdrop WD on the frosted glass 52 isphotographed by the high-speed camera 54 in this state.

The PC 57 processes an image photographed by the high-speed camera 54,and obtains the particle size of the waterdrop WD. In this case, the PC57 analyzes the photographed image including the waterdrop WD and thescale 53 to obtain a length on the photographed image corresponding to 1(mm) of the scale 53, and the particle size of the waterdrop WD on thephotographed image, so that the actual particle size of the waterdrop WDis obtained from a ratio of these two values. Then, the PC 57 processesthe image photographed by the high-speed camera 54 to obtain the flowspeed of the waterdrop WD (equivalent to the moving speed of thewaterdrop WD). In this case, the PC 57 analyzes the photographed imageincluding the waterdrop WD and the scale 53 to obtain an actual movingdistance (obtained by a method similar to the above method for obtainingthe particle size of the waterdrop WD) from a distance on thephotographed image where the waterdrop WD moves during the predeterminednumber of frames, so that the flow speed of the waterdrop WD is obtainedfrom this actual moving distance. Then, a measurer visually recognizesthe water film WF and the waterdrop WD included in the photographedimage to determine whether or not water splash occurs by collision ofthe waterdrop WD with the water film WF. The “water splash” mentionedherein means that the waterdrop WD collides with the water film WF, thewater film WF is lifted, the lifted water film WF bursts (splits), and awaterdrop splashes.

FIGS. 5A and 5B illustrate examples of a measurement result obtained bythe measurement system 50 according to the embodiment of the presentinvention. More specifically, FIGS. 5A and 5B illustrate examples ofphotographed images when the particle sizes of the waterdrop WD areconstant, and the flow speeds of the waterdrop WD are different. Morespecifically, FIG. 5A illustrates an example of a photographed imagewhen the flow speed of the waterdrop WD is 3 (m/sec), FIG. 5Billustrates an example of a photographed image when the flow speed ofthe waterdrop WD is 5 (m/sec), and the particle size of the waterdrop WDis fixed to 750 (μm) when these flow speeds are applied. In addition,the incident angle of the waterdrop WD to the frosted glass 52(including the water film WF) is fixed to 90 degrees. In each of FIGS.5A and 5B, the photographed images are arranged in order from the leftto the right in time series. For convenience of explanation, imagescorresponding to the waterdrop WD are circled, and bars are added to thevicinity of places where water splash occurs on the images.

As illustrated in FIG. 5A, it is found that water splash does not occur(refer to reference numeral A21), in a case where the flow speed of thewaterdrop WD is 3 (m/sec). As illustrated in FIG. 5B, it is found thatwater splash occurs (refer to reference numeral A22), in a case wherethe flow speed of the waterdrop WD is 5 (m/sec). Consequently, it can besaid that water splash is likely to be caused, when the flow speed ofthe waterdrop WD becomes large.

FIGS. 6A and 6B are diagrams illustrating another example of ameasurement result obtained by the measurement system 50 according tothe embodiment of the present invention. More specifically, FIGS. 6A and6B illustrate examples of photographed images when the flow speeds ofthe waterdrop WD are constant, and the particle sizes of the waterdropWD are different. More specifically, FIG. 6A illustrates an example of aphotographed image when the particle size of the waterdrop WD is 400(μm), FIG. 6B illustrates an example of a photographed image when theparticle size of the waterdrop WD is 820 (μm), and the flow speed of thewaterdrop WD is fixed to 4 (m/sec) when the above particle sizes areapplied. In addition, the incident angle of the waterdrop WD to thefrosted glass 52 (including the water film WF) is fixed to 90 degrees.In each of FIGS. 6A and 6B, the photographed images are arranged inorder from the left to the right in time series. For convenience ofexplanation, images corresponding to the waterdrop WD are circled, andbars are added to the vicinity of places where water splash occurs onthe images.

As illustrated in FIG. 6A, it is found that water splash does not occur(refer to reference numeral A31), in a case where the particle size ofthe waterdrop WD is 400 (μm). As illustrated in FIG. 6B, it is foundthat water splash occurs (refer to reference numeral A32), in a casewhere the particle size of the waterdrop WD is 820 (μm). Consequently,it can be said that water splash is likely to be caused, when theparticle size of the waterdrop WD becomes large.

In this embodiment, the flow speed and the particle size of thewaterdrop WD jetted from the water discharging device 51 were set torespective various values, and it was measured whether or not watersplash occurs in combinations of various flow speeds and particle sizesby the above method. The results are illustrated in FIG. 7.

FIG. 7 is a diagram illustrating the presence or absence of water splashmeasured in the combinations of the various flow speeds and particlesizes applied to the waterdrop, and a diagram for illustrating an upperlimit boundary line of the average flow speed and the average particlesize of waterdrops jetted from the water discharging device 2 accordingto the embodiment of the present invention.

In FIG. 7, a horizontal axis represents the flow speed (m/sec) of thewaterdrop, and a vertical axis represents the particle size (μm) of thewaterdrop. More specifically, the circles drawn by “◯” in FIG. 7 denotea flow speed and a particle size when it is determined by measurementthat water splash does not occur, and the crosses drawn by “×” in FIG. 7denote a flow speed and a particle size when it is determined bymeasurement that water splash occurs. By such measurement results, aregion defined by the flow speed and the particle size can be dividedinto a region R1 where water splash occurs, and a region R2 where watersplash does not occur, by using a curved line L1 illustrated in FIG. 7as a boundary line. This curved line L1 can be expressed by thefollowing approximate expression (3) by using a flow speed x (m/sec) anda particle size y (μm).

y=9300×x ^((−1.5))  (3)

In this embodiment, the curved line L1 expressed by the above expression(3) is used as the upper limit boundary line of the average flow speedand the average particle size of waterdrops jetted from the waterdischarging device 2. That is, as a conditional expression which theaverage flow speed X (m/sec) and the average particle size Y (μm) of thewaterdrops jetted from the water discharging device 2 should satisfy,the following expression (4) based on the expression (3) is used. Whensuch expression (4) is satisfied by the average flow speed X (m/sec) andthe average particle size Y (μm) of the waterdrops jetted from the waterdischarging device 2, it is possible to suitably inhibit water splash bythe waterdrops jetted from the water discharging device 2.

Y≦9300×X ^((−1.5))  (4)

(2) Lower Limit Boundary Line of Flow Speed and Particle Size

Now, the lower limit boundary line of the average flow speed and theaverage particle size of waterdrops jetted from the water discharge part13 of the water discharging device 2 according to this embodiment willbe described. This lower limit boundary line is determined from aviewpoint of securing washing performance (dirt removingperformance/hand washing performance) by the water discharging device 2of this embodiment.

In this embodiment, in order to obtain the above lower limit boundaryline, the following measurement procedure is performed. First,pseudo-dirt containing ethanol and Sudan Red at a mass ratio of “6:1” iscreated. Next, the created pseudo-dirt of 0.2 (cc) is adhered to afrosted glass with a size of 80 (mm)×80 (mm). Then, the frosted glass towhich the pseudo-dirt is adhered is left for a minute, the pseudo-dirtspreads throughout the frosted glass by its own weight, and thereafterthe frosted glass to which the pseudo-dirt is adhered is heated at 50 (°C.) for two minutes by a hot plate to be dried. Then, the waterdischarging device discharges water toward the center of the frostedglass for 5 seconds. In this case, the water discharge port of the waterdischarging device and a surface of the frosted glass are separated by80 (mm).

The frosted glass to which the above water discharge is performed isheated at 50 (° C.) for a minute by the hot plate to be dried, andthereafter is put into a Petri dish. Next, oleic acid of 20 (cc) isdropped in a Petri dish, and the pseudo-dirt is separated from thefrosted glass. Then, oleic acid and the pseudo-dirt are collected, andput into an exclusive container of a spectrophotometer to be measured.Then, a dirt removing ratio (the smaller the value is, the higher thepseudo-dirt removing degree is) indicating a pseudo-dirt removing degreeis obtained from a value obtained by measurement using thisspectrophotometer. More specifically, first, in order to previouslyperform 0 correction of the spectrophotometer, a measured value obtainedwhen only oleic acid is used is previously obtained, the frosted glasswhich is in a state where the above water discharge is not performed(that is, a state where 100% of the pseudo-dirt of 0.2 (cc) remains) ispreviously measured, and a measured value obtained when the dirtremoving ratio is a maximum value (100%) is previously obtained. Then,on the basis of the previously obtained measured values thus obtained, adirt removing ratio (decrease rate) corresponding to a value obtained bymeasurement using the exclusive container of the spectrophotometercontaining the collected oleic acid and pseudo-dirt this time isobtained.

Herein, as water discharge performed to the frosted glass to which thepseudo-dirt is adhered, spray water discharge by the water dischargingdevice 2, and foamy water discharge at 2 liters per minutes wereapplied, and the measurement results were obtained by the aboveprocedure under a similar condition. More specifically, in a case wherethe spray water discharge is applied, the flow speeds and the particlesizes of waterdrops jetted by the water discharging device 2 werevariously changed to be measured. In this case, various types of thewater discharge part 13 are applied to the water discharging device 2(consequently, the flow rate by the water discharge part 13 is changed),so that the flow speeds and the particle sizes of the jetted waterdropswere changed.

By thus measurement, in foamy water discharge at 2 liters per minute, adirt removing ratio of 22 (%) was obtained. Then, from measurementresults obtained in a case where the above spray water discharge isused, the flow speed and the particle size when the same degree of adirt removing ratio as a dirt removing ratio of 22 (%) by the foamywater discharge at 2 liters per minute were extracted. The results areillustrated in FIG. 8.

FIG. 8 is a diagram illustrating the results of the flow speed and theparticle size in a case where a dirt removing ratio of about 22 (%) isobtained by spray water discharge, and is a diagram for illustrating alower limit boundary line of the average flow speed and the averageparticle size of waterdrops jetted from the water discharging device 2according to the embodiment of the present invention.

In FIG. 8, a horizontal axis represents the flow speed (m/sec), and avertical axis represents the particle size (μm). More specifically, thetriangles drawn by “▴” in FIG. 8 denote the flow speed and the particlesize in the case where a dirt removing ratio of about 22 (%) isobtained. By such results, relation between the flow speed x (m/sec) andthe particle size y (μm) in the case where a dirt removing ratio ofabout 22 (%) is obtained can be expressed by the following approximateexpression (5) corresponding to a straight line L2 illustrated in FIG.8.

y=−360×x+1500  (5)

In this embodiment, the lower limit boundary line of the average flowspeed and the average particle size of the waterdrops jetted from thewater discharging device 2 is defined by the straight line L2 expressedby the above Expression (5). That is, as a conditional expression whichthe average flow speed X (m/sec) and the average particle size Y (μm) ofthe waterdrops jetted from the water discharging device 2 shouldsatisfy, the following expression (6) based on the expression (5) isused. When such expression (6) is satisfied by the average flow speed X(m/sec) and the average particle size Y (μm) of the waterdrops jettedfrom the water discharging device 2, the same degree of a dirt removingratio as the dirt removing ratio by the foamy water discharge at 2liters per minute can be implemented by the spray water discharge of thewater discharging device 2. That is, it is possible to secure suitablewashing performance by the spray water discharge of the waterdischarging device 2.

Y≧−360×X+1500  (6)

(3) Lower Limit Value of Flow Speed

Now, the lower limit value of the average flow speed of the waterdropsjetted from the water discharge part 13 of the water discharging device2 according to this embodiment will be described. This lower limit valueis determined from a viewpoint of formation of suitable spray waterdischarge by the water discharging device 2 of this embodiment.

As described above, in this embodiment, a water discharge form in whichwater spreads in a range larger than the opening diameter of the waterdischarge port 13 a of the water discharge part 13 to be intermittentlydischarged is applied as the spray water discharge. Whether or not suchspray water discharge is suitably formed depends on the flow speed(uniquely equivalent to the flow rate) applied to the water dischargingdevice 2. This will be specifically described with reference to FIG. 9.

FIG. 9 is a diagram illustrating a specific example of the waterdischarge form by the water discharging device 2 in a case where theflow rate applied to the water discharging device 2 according to theembodiment of the present invention is variously changed. FIG. 9illustrates a photographed image that illustrates a water discharge formin a case where a flow rate of 0.2 (L/min) is applied, a photographedimage that illustrates a water discharge form in a case where a flowrate of 0.15 (L/min) is applied, a photographed image that illustrates awater discharge form in a case where a flow rate of 0.1 (L/min) isapplied, and a photographed image that illustrates a water dischargeform in a case where a flow rate of 0.05 (L/min) is applied, in orderfrom the left.

From FIG. 9, it is found that at flow rates of 0.1 to 0.2 (L/min),suitable spray water discharge is performed by the water dischargingdevice 2, that is, water spreads in the range larger than the openingdiameter of the water discharge port 13 a to be intermittentlydischarged. On the other hand, it is found that at a flow rate of 0.05(L/min), suitable spray water discharge is not formed by the waterdischarging device 2, that is, water does not spread in the range largerthan the opening diameter of the water discharge port 13 a and is notintermittently discharged. This is because at a low flow rate, arotational flow (refer to the arrow A 12 in FIG. 3) necessary forforming the suitable spray water discharge cannot be formed inside thewater discharge part 13.

Therefore, in this embodiment, a flow speed corresponding to the aboveflow rate of 0.05 (L/min) is used as a lower limit value of the averageflow speed of the waterdrops jetted from the water discharge part 13 ofthe water discharging device 2. In a case where the opening diameter ofthe water discharge port 13 a of the water discharge part 13 is 0.8(mm), a flow speed of about 1.7 (m/sec) is obtained from across-sectional area corresponding to an opening diameter of 0.8 (mm),and a flow rate of 0.05 (L/min) described above by use of a theoreticalformula of “flow rate=cross-sectional area×flow speed”. In thisembodiment, 1.7 (m/sec) is used as the lower limit value of the averageflow speed of the waterdrops jetted from the water discharging device 2.When such 1.7 (m/sec) is applied, and the average flow speed of thewaterdrops jetted from the water discharging device 2 is set to be 1.7(m/sec) or more, suitable spray water discharge can be formed by thewater discharging device 2, that is, water can spread in the rangelarger than the opening diameter of the water discharge port 13 a to beintermittently discharged.

(4) Lower Limit Value of Particle Size

Now, a lower limit value of the average particle size of the waterdropjetted from the water discharge part 13 of the water discharging device2 according to this embodiment will be described. This lower limit valueis determined from a viewpoint of suitably lowering the waterdropsjetted from the water discharging device 2 of this embodiment withoutfloating the waterdrops.

In this embodiment, it is considered to define the lower limit value ofthe average particle size by using the following expression (7) obtainedby converting general Stokes' law.

$\begin{matrix}{d = \sqrt{\frac{18\; \eta \; v}{( {\rho_{p} - \rho_{f}} )g}}} & (7)\end{matrix}$

In the expression (7), “d” denotes a particle size, “η” denotes theviscosity of water, “v” denotes a terminal speed, “ρ_(p)” denotes thedensity of water, “ρ_(f)” denotes the density of air, and “g” denotesgravitational acceleration. The terminal speed v is a speed when bodyforce such as gravity and centrifugal force and drag which depends on aspeed are balanced and are not changed in a case where an objectreceives the body force and the drag. In this case, the object singlymoves, that is, even when another object exists, the object moveswithout being influenced by another object. In the expression (7), it isassumed that the speed of a particle traveling vector is zero, and anobject actually freely falls in the gravity direction.

In this embodiment, in the above expression (7), the particle size dwhen terminal speed v≅0 is satisfied is used as the lower limit value ofthe average particle size. This is because a state of terminal speed v≅0is equivalent to a state where the waterdrops jetted from the waterdischarging device 2 float without lowering. When the terminal speed vis 0, the expression (7) is not established, and therefore 1 (mm/sec) issubstituted into the expression (7) as the terminal speed v.Additionally, values of water viscosity η, water density ρ_(p), and airdensity ρ_(f) when a water temperature and an air temperature are 5° C.are substituted into the expression (7). Consequently, a particle size dof about 35 (μm) is obtained.

In this embodiment, 35 (μm) thus obtained is used as the lower limitvalue of the average particle size of the waterdrops jetted from thewater discharging device 2. When the average particle size of thewaterdrops jetted from the water discharging device 2 is set to be 35(μm) or more by applying 35 (μm), the waterdrops jetted from the waterdischarging device 2 can be suitably lowered without floating.Consequently, the waterdrops jetted from the water discharging device 2can suitably reach, for example, hands of a user.

(5) Upper Limit Value of Particle Size

Now, an upper limit value of the average particle size of the waterdropjetted from the water discharge part 13 of the water discharging device2 according to this embodiment will be described.

According to measurement performed by the inventors of the presentinvention, it is found that when the particle size of the waterdropjetted from the water discharging device 2 exceeds 9000 (μm), thewaterdrop splits without maintaining the particle size even in awindless state. Thus, when the waterdrops jetted from the waterdischarging device 2 split on the way, control becomes difficult, andwater splash cannot be suitably inhibited.

Therefore, in this embodiment, from a viewpoint of suitably maintainingthe particle sizes of the waterdrops jetted by the water dischargingdevice 2 so as not to cause the waterdrops to split, the upper limitvalue of the average particle size of the waterdrops jetted from thewater discharging device 2 is defined. More specifically, in thisembodiment, from the above measurement results, the average particlesize of the waterdrops jetted from the water discharging device 2 is setto be 9000 (μm) or less by using 9000 (μm) as the upper limit value ofthe average particle size of the waterdrops jetted from the waterdischarging device 2.

(6) Suitable Range of Flow Speed and Particle size

Now, a suitable range of the average flow speed and the average particlesize of the waterdrops jetted from the water discharge part 13 of thewater discharging device 2 according to this embodiment, in accordancewith contents described in the above (1) to (5) will be described withreference to FIG. 10.

FIG. 10 is an explanatory diagram of the suitable range of the averageflow speed and the average particle size of the waterdrops jetted fromthe water discharging device 2 according to the embodiment of thepresent invention. In FIG. 10, a horizontal axis represents the flowspeed (m/sec), and a vertical axis represents the particle size (μm).More specifically, in FIG. 10, in addition to the curved line L1 and thestraight line L2 (refer to FIG. 7 and FIG. 8) described the above (1),(2), a straight line L3 corresponding to 1.7 (m/sec) which is the lowerlimit value of the average flow speed described in the above (3), astraight line L4 corresponding to 35 (μm) which is the lower limit valueof the average particle size described in the above (4), a straight lineL5 corresponding to 9000 (μm) which is the upper limit value of theaverage particle size described in the above (5) are overlapped.

As illustrated in FIG. 10, in this embodiment, the flow speed and theparticle size in a range R3 defined by the curved line L1 and thestraight lines L2 to L5 are applied as the average flow speed and theaverage particle size of the waterdrops jetted from the waterdischarging device 2 so as to satisfy all conditions described in theabove (1) to (5).

Working Effects According to This Embodiment

Now, working effects of the water discharging device according to theembodiment of the present invention will be described.

According to this embodiment, in the water discharging device 2 thatperforms spray water discharge enabling water saving and water dischargeover a wide range, the average flow speed and the average particle sizeof the waterdrops jetted from this water discharging device 2 satisfiesthe above conditional expression (4), so that it is possible to suitablyinhibit water splash by the waterdrops jetted from the water dischargingdevice 2.

According to this embodiment, the average flow speed and the averageparticle size of the waterdrops jetted from the water discharging device2 satisfy the above conditional expression (6), so that it is possibleto secure suitable washing performance (such as hand washingperformance) by spray water discharge of the water discharging device 2.

According to this embodiment, the average flow speed of the waterdropsjetted from the water discharging device 2 is set to 1.7 (m/sec) ormore, so that it is possible to form suitable spray water discharge bythe water discharging device 2. That is, it is possible to suitablyimplement a water discharge form in which water spreads in a rangelarger than the opening diameter of the water discharge port 13 a to beintermittently discharged.

According to this embodiment, the average particle size of thewaterdrops jetted from the water discharging device 2 is set to 35 (μm)or more, so that the waterdrops jetted from the water discharging device2 can be suitably lowered without floating. Consequently, the waterdropsjetted from the water discharging device 2 can suitably reach, forexample, hands of a user.

According to this embodiment, the average particle size of thewaterdrops jetted from the water discharging device 2 is set to 9000(μm) or less, so that it is possible to suitably inhibit split of thewaterdrops jetted from the water discharging device 2 on the way.Consequently, it is possible to easily perform control for inhibitingwater splash.

According to this embodiment, the discharge angle θ (refer to FIG. 3)from the water discharge port 13 a of the water discharging device 2 isset to 40 to 50 degrees, whole hands of a user can be covered by spraywater discharge from the water discharging device 2, and hand washingperformance can be improved.

Modification

In the above embodiment, the average flow speed and the average particlesize of the waterdrops jetted from the water discharging device 2satisfy all the conditions of (1) to (5) described in the section of<Flow Speed and Particle Size of Spray Water Discharge>. However, thepresent invention is not limited to this. In another example, theaverage flow speed and the average particle size of the waterdropsjetted from the water discharging device 2 may satisfy at least onecondition of any of (1) to (5) (including various combinations of theconditions of (1) to (5)).

In the above embodiment, general tap water (city water) is dischargedfrom the water discharging device 2. However, in place of this, forexample, functional water (that is, disinfected water) having adisinfecting function such as electrolyzed water may be discharged. Inone example, an electrolysis tank may be provided on an upstream side ofa flow path 15 of a water discharging device 2, and electrolyzed watergenerated by this electrolysis tank may be discharged from a waterdischarge part 13.

In the above embodiment, the example in which the present invention isapplied to a hand wash basin (refer to FIG. 1) is described. However,the application of the present invention is not limited to this. Inanother example, the present invention can be applied to a kitchen.

FIG. 11 is a perspective view of a kitchen as viewed obliquely fromabove, the kitchen being a kitchen to which a water discharging deviceaccording to a modification in the embodiment of the present inventionis applied. A kitchen 5 illustrated in FIG. 11 mainly has a waterdischarging device 6 that mistily performs water discharge (spray waterdischarge/misty water discharge) in which water spreads from a waterdischarge port as illustrated by reference numeral M, a sink 7 thatreceives the water discharged from this water discharging device 6 todrain the water from a drain port (not illustrated), and serves as awater receiving part. A configuration similar to the configuration ofthe water discharging device 2 according to the above embodiment isapplied to the water discharging device 6 of such a kitchen 5, so thatworking effects similar to the working effects of the contents describedin the section of <Working Effects according to This Embodiment> areobtained.

REFERENCE SIGNS LIST

1 hand wash basin

2, 6 water discharging device

3 bowl

5 kitchen

6 sink

11 water discharge pipe

13 water discharge part

13 a water discharge port

15 flow path

1. A water discharging device that is provided so as to secure apredetermined opened space with respect to a water receiving part, anddischarges water toward the water receiving part, the water dischargingdevice comprising, a water discharge part that jets waterdrops so as tospread the waterdrops at a predetermined angle from a water dischargeport, and is set so as to discharge water at a predetermined flow rate,wherein an average flow speed X (m/sec) and an average particle size Y(μm) of the waterdrops jetted from the water discharge part satisfy afollowing conditional expression (1).Y≦9300×X ^((−1.5))  (1)
 2. The water discharging device according toclaim 1, wherein the average flow speed X and the average particle sizeY of the waterdrops jetted from the water discharge part further satisfya following conditional expression (2).Y≧−360×X+1500  (2)
 3. The water discharging device according to claim 1,wherein the average flow speed X of the waterdrops jetted from the waterdischarge part is equal to or larger than 1.7 (m/sec).
 4. The waterdischarging device according to claim 1, wherein the average particlesize Y of the waterdrops jetted from the water discharge part is equalto or larger than 35 (μm).
 5. The water discharging device according toclaim 1, wherein the average particle size Y of the waterdrops jettedfrom the water discharge part is equal to or smaller than 9000 (μm). 6.The water discharging device according to claim 1, wherein the waterdischarge part jets the waterdrops so as to spread the waterdrops atfrom 40 to 50 degrees as the predetermined angle.